Neuropathic dental pain
A high percentage of patients that are surgically treated for trigeminal neuralgia consult their dentist first and receive possibly unjustified dental treatment. Differential diagnoses include odontogenic pain syndromes as well as atypical orofacial pain. The present literature acknowledges difficulties in correctly diagnosing trigeminal neuralgia, but seems to underestimate the extent 1).
A literature search and review of the database identified 3 potential thalamic targets. A directional lead was implanted in a patient with NDP and its current steering used to test the effects in each nucleus. The patient reported her pain after 2 wk of stimulation in a prospective randomized blinded clinical trial of one. Quality of life measurements were performed before and after 3 mo on their best setting.
They identified 3 potential nuclei: the Centromedian nucleus (CM), Ventral posteromedial nucleus (VPM), and Anterior pulvinar nucleus. The best results were during VPM stimulation (>90% reduction in pain) and CM stimulation (50% reduction). Following 3 mo of VPM-DBS in combination of lateral CM stimulation, their pain disability index dropped (from 25 to 0) and short form 36 improved (from 67.5 to 90).
VPM stimulation in combination with CM stimulation is a promising target for NDP. DBS electrode directionality can be used to test multiple targets and select a patient specific “sweet spot” for NDP treatment 2).
Imholz et al. discuss 2 rare cases of patients who presented with a cerebellopontine angle tumor, who initially manifested with symptoms of dental pain.
The first patient, male, 44 years of age presented to his dentist with toothache (47), which led to its extraction. Five months later, a second painful episode, more characteristic, revealed the presence of a vestibular schwannoma, which was successfully treated and led to the disappearance of the pain. The second case, a 43-year-old female presented to her dentist with toothache (46), which lead the dentist perform a root filling. Two years later, with a 3rd episode of dental pain, more relevant of a trigeminal nevralgia, a epidermoid cyst of the right cerebellopontine angle was identified and successfully treated leading to the disappearance of the pain.
Cerebellopontine angle tumors of this type may lead, in exceptional cases to symptoms of dental pain. Therefore, in face of atypical tooth or facial pain, both a detailed medical history and a detailed examination are necessary, in order to investigate any neurological signs and symptoms, before undertaking any non-essential dental treatment, which may be detrimental for the patients 3).